Asphalt has been employed for numerous and wide variety of applications for many years. One of the problems encountered with asphalt is that its adhesion to various substrates and especially to aggregate needs to be improved. Such aggregate is represented, for example, by gravel, crushed rock, slag, sand and crushed limestone. Additionally, the adhesion of asphalt needs to be improved with respect to other material such as, for example, cementitious materials, metals, glass and the like.
In accordance with the present invention, improved asphalt compositions are provided which composition is the product produced by reacting an acrylamide with asphalt that has been prereacted with a vinyl aromatic monomer and a rubbery polymer, the reacting optionally being done in the presence of a vinyl aromatic monomer which may be the same as or different than the vinyl aromatic monomer employed in producing the prereacted asphalt. Styrene is preferred in both instances.
Some of the desirable properties of the present compositions include improved coatability of negatively charged surfaces, improved adhesion, less stripping, improved emulsifiability, improved flexibility, particularly at low temperatures, improved strength, reduced high temperature flow, increased durability, better compatibility with polymers.
These compositions will find utility for a wide variety of purposes. They, for example, will find application in the highway and bridge construction, repair and maintenance areas as, for example, crack and pothole fillers, joint sealers, and water resistant membranes, as well as cut-backs with the compositions being used alone or as blends with conventional asphalts. These compositions can be formed into emulsions with conventional asphalt emulsifiers to form a slow set emulsion, having utility for slurry seal applications, or as a cold overlay. Preferably non-ionic surfactants are used as emulsifiers. The compositions may also be employed as corrosion resistant and/or water resistant coatings for metals and as coatings and/or impregnants for glass, especially glass fibers. Such coated or impregnated glass fibers will show outstanding compatibility with conventional asphalt and consequently will serve as outstanding reinforcements for such asphalts.